bump libbson to 1.4.0-beta0

ajdavis · ajdavis · commit 8204eb83a3e7 · 2016-07-27T12:50:51.000-04:00
diff --git a/src/libbson b/src/libbson
@@ -1 +1 @@
-Subproject commit 66dfe2b330f07c8a3c37684db84cfa75972ad413
+Subproject commit 3a34a65fe6ce41618ee3bb3b0b697fb7571a21b8
